Motivating Strategic and Coordinated Sea-Level Rise Adaptation in Urban Estuaries: A Case Study of Physical and Economic Feedbacks in San Francisco Bay, CA, USA

Abstract:

Sea-level rise (SLR) threatens coastal regions globally, leading to more frequent and severe coastal inundation that impacts homes, businesses, and critical infrastructure systems. Coastal communities are now wrestling with how to effectively adapt their shorelines to mitigate the threat of future flooding. A critical challenge to this response is that decisions about coastal flood mitigation strategies are often made by individual communities or private entities, with limited cross-jurisdictional coordination and at a scale that does not match the hydrodynamic extent of the threat. In estuarine systems, these individual decisions affect the spatial and temporal interactions between hydrodynamics and shoreline configuration, which can alter local and baywide tidal wave propagation, patterns of inundation, and related property damage and impose externalities (both positive and negative) on other parties. Understanding the relative influence of local shoreline modification decisions on tidal dynamics with SLR is thus critical to effective management of coupled natural-human systems in coastal regions.

Here we couple dynamic simulations of coastal inundation with building damage models to examine how SLR and local shoreline protection scenarios affect tidal dynamics, coastal inundation, and associated economic externalities in the densely-populated San Francisco Bay Area, where strong regional hydrodynamic interactions and complex jurisdictional boundaries motivate the adoption of a coordinated, regional planning approach. We apply our analysis at the scale of the operational landscape unit (OLU). OLUs represent areas with similar physical and ecological processes that provide a cohesive set of ecosystem services. In the context of SLR adaptation, OLUs can provide a level of refinement to large-scale shoreline adaptation strategies while maintaining the integrity of ecosystems by forgoing traditional political boundaries. Our results highlight opportunities for applying strategic and coordinated flood accommodation and protection approaches at the OLU scale to achieve regional flood reduction benefits and demonstrate the importance of using integrated assessment models that account for interactions between natural processes and human decision-making in climate adaptation.